Scientists spoke with Salon about the diseases and pathogens that will be exacerbated by climate change
In the popular HBO series “The Last of Us,” humanity faces a dangerous fungus that emerges as a result of climate change and transforms people into zombies. Even though “The Last of Us” is a science fiction thriller and its fungus might actually rescue the planet rather than end it, the idea that pandemics or epidemics could be brought on by climate change is not just a theory. A flesh-eating bacteria known as vibrio vulnificus was found to be infecting eight times as many people as it did 30 years ago (from 10 patients annually to 80), which is worrying given that the disease can be deadly to up to 1 in 5 of those who contract it. The most plausible reason for the increase in infections? the ocean warming as a result of climate change.
As it turns out, human species may only be beginning to deal with waves of fatal diseases after the COVID-19 pandemic. The same cannot be true, however, of some of these other deadly viruses that may be hiding in our collective future if global warming continues to run amok. There is no evidence that COVID-19 was connected to humanity’s ongoing issue of excessive greenhouse gas emissions. These are only a handful of the most well-known diseases, disorders, and pathogens that will spread more widely as the Earth heats. Others, like SARS-CoV-2, a virus that may have spread from animals to people for reasons related to climate change, may exist but are as of yet undiscovered by science.
Mentally ill
Even if actual infections do not affect people, this does not preclude the possibility of pandemics caused by climate change. Numerous studies have previously shown that people are experiencing anxiety, sleeplessness, and depression connected to climate change. It makes natural that people would feel dissatisfied, powerless, and despondent as a result of the Earth’s controllable — yet stubbornly uncontrollable — warming, given that the super-rich are responsible for the vast bulk of climate change (despite their assertions to the contrary).
Dengue infection
Like malaria, dengue fever is spread by mosquitoes and is highly dangerous to people. The WHO tells the public that dengue fever is mostly asymptomatic and that when symptoms do appear, they are typically minor and include fevers, rashes, headaches, and body aches. However, people who have a severe case of dengue fever may experience symptoms like prolonged vomiting, excruciating stomach pain, bloody feces and vomit, persistent thirst, and generalized weakness. The CDC estimates that 400 million individuals worldwide are presently infected with dengue each year, albeit only around 100 million of them will develop symptoms and 21,000 will pass away.
Leishmaniasis
Sand flies, which are typically about one-fourth the size of a mosquito, spread leishmaniasis rather than mosquitoes. According to the Pan American Health Organization, this illness affects between 900,000 and 1.6 million individuals annually, and of that total, 20,000 to 30,000 people will pass away. The most prevalent and least harmful type of the illness is cutaneous leishmaniasis, which causes sores that, if left untreated, can develop into ulcers that are frequently followed by scabs or crusts. These rarely cause pain, but sometimes do. Contrarily, visceral leishmaniasis can be fatal and affects multiple internal organs, with bone marrow, the liver, and the spleen being the most frequently affected.
In a 2010 peer-reviewed study on the disease, researchers stated that “Climate change will exacerbate the ecological risk of human exposure to leishmaniasis in areas north of the present range of the disease in the United States (particularly the east-central part of the country) and possibly even in some parts of south-central Canada.”
Malaria
Dr. Jeff Harvey, a special professor of biological conservation and advocacy at the Free University in Amsterdam, responded to Salon’s inquiry about pandemics and climate change by warning of “various insect-transmitted pathogens found on tropical ecosystems such as malaria, dengue fever, leishmaniasis, etc.” The explanation is straightforward: Many of the climate change conditions that would kill off vast numbers of people, such as increased heat and continual movement of large animal populations, are favorably paradisal for mosquitoes.
The Centers for Disease Control and Prevention (CDC) states that malaria, the first mosquito-borne ailment identified by Harvey, causes “high fevers, shaking chills, and flu-like illness.” Plasmodium falciparum, P. vivax, P. ovale, P. malariae, P. knowlesi, and the highly deadly P. falciparum are among the parasites that transmit this mosquito-borne disease. Out of 241 million clinically confirmed cases, the World Health Organization (WHO) predicts that 627,000 people will die from malaria infections year 2020.
Zika
At the University of Florida, Dr. Sadie Jane Ryan holds joint appointments in geography and the Emerging Pathogens Institute (EPI). She is an associate professor of medical geography. In an email to Salon, Ryan added malaria and dengue to the list of illnesses that would spread more widely as a result of climate change and mosquitoes. She also brought up the similarly carried by mosquitoes zika virus. Fortunately, the symptoms of the zika virus are typically fairly minor and include fever, headaches, muscle discomfort, joint pain, and rashes.The New England Journal of Medicine notes that the zika virus is linked to issues during and after pregnancy; for example, “the mortality rate was 52.6 deaths per 1000 person-years among live-born children with congenital Zika syndrome, as compared with 5.6 deaths per 1000 person-years among those without the syndrome.”
Illnesses spread by ticks
According to Ryan, “Tick-borne diseases are less directly influenced by the climate because a lot of their ecology is mediated by landscape factors and their hosts, but that is all changing due to climate change, as shown by studies on the relationship between climate and tick-borne diseases.”
Ticks won’t hesitate to relocate as the environment warms and will bring their many pathogens with them. This is true whether we’re talking about unsightly diseases like babesiosis and anaplasmosis or the most infamous tick-borne sickness, Lyme disease. Ticks like conditions when the humidity is above 85%, the air temperature is greater than 6°C but less than 7°C, and they are near a lot of blood-delivering hosts. This is a part of a bigger pattern of pests flourishing as the Earth warms, according to an article from the scientific journal eLife at the time. According to population genetics theory, evolutionary adaptation is most likely for short-lived species with high population growth rates, which are characteristics of many pest, pathogen, and vector species, the authors wrote. “While climate adaptation has typically been studied in the context of conservation biology.